This presentation illustrates the experience gained by me while working on fabricating a Successive Approximation ADC on a MOSIS chip. This was part of a project-oriented course at UT. The chip is currently being fabricated by MOSIS and will be available by mid-April for testing.

1. EECS 631: FINAL PROJECT
Successive Approximation ADC
Project Team:
Ankit Master
Kevin Tham

2. Design Specifications
• Dynamic Range: 0 – 4V
• Supply Voltage: 5V
• Resolution: 7-bit
• 1 LSB: 31.25mV
• Speed/Clock Frequency: 10 MHz
• Sampling rate : 100 ksps
Ankit Master & Kevin Tham University of Tennessee, Knoxville

3. Architecture
Complete architecture implementation (Ref: CMOS Analog Circuit Design by Allen & Holdberg)
Ankit Master & Kevin Tham University of Tennessee, Knoxville

4. Logic module
Ankit Master & Kevin Tham University of Tennessee, Knoxville

5. 1) Vin = 0.9 V
Logic Operation
Step Q6Q5Q4Q3Q2Q1Q0 B’6B’5B’4B’3B’2B’1B’0 Vdac_out (V) Vcomp B6B5B4B3B2B1B0
1 1000000 1000000 2 1 0000000
2 0100000 0100000 1 1 0000000
3 0010000 0010000 0.5 0 0010000
4 0001000 0011000 0.75 0 0011000
5 0000100 0011100 0.875 0 0011100
6 0000010 0011110 0.9375 1 0011100
7 0000001 0011101 0.89625 0 0011101
2) Vin = 2.3 V
Step Q6Q5Q4Q3Q2Q1Q0 B’6B’5B’4B’3B’2B’1B’0 Vdac_out (V) Vcomp B6B5B4B3B2B1B0
1 1000000 1000000 2 0 1000000
2 0100000 1100000 3 1 1000000
3 0010000 1010000 2.5 1 1000000
4 0001000 1001000 2.25 0 1001000
5 0000100 1001100 2.375 1 1001000
6 0000010 1001010 2.3125 1 1001000
7 0000001 1001001 2.28125 0 1001001

6. Pre-layout simulation

7. Layout
Ankit Master & Kevin Tham University of Tennessee, Knoxville

8. Post-Layout simulation

9. Reset circuitry
Ankit Master & Kevin Tham University of Tennessee, Knoxville

10. Pre-layout Simulation
Ankit Master & Kevin Tham University of Tennessee, Knoxville

11. Layout
Ankit Master & Kevin Tham University of Tennessee, Knoxville

12. Post-layout simulation
Ankit Master & Kevin Tham University of Tennessee, Knoxville

13. Opamp
Ankit Master & Kevin Tham University of Tennessee, Knoxville

14. Post-layout simulation
Ankit Master & Kevin Tham University of Tennessee, Knoxville

15. DAC module
Ankit Master & Kevin Tham University of Tennessee, Knoxville

16. DAC Layout
Ankit Master & Kevin Tham University of Tennessee, Knoxville

17. Post-layout simulation
Ankit Master & Kevin Tham University of Tennessee, Knoxville

18. Track and hold
Left: Schematic
Bottom: Layout

19. Comparator module
Ankit Master & Kevin Tham University of Tennessee, Knoxville

20. Comparator Layout
Ankit Master & Kevin Tham University of Tennessee, Knoxville

21. Top level Design
Ankit Master & Kevin Tham University of Tennessee, Knoxville

22. Pre-layout Simulation
Ankit Master & Kevin Tham University of Tennessee, Knoxville

23. Post-layout Simulation
Ankit Master & Kevin Tham University of Tennessee, Knoxville

24. Padframe
Ankit Master & Kevin Tham University of Tennessee, Knoxville